IEDs, or “improvised explosive devices”, are popular tools for terrorists. An IED typically consists of an explosive charge, a detonator (i.e., blasting cap), and an initiator used for causing the detonator to explode. One of the most common devices used as an initiator is a mobile terminal (hereinafter, also referred to as cell phone, or mobile phone). The IED can be triggered (initiated) from a remote location by calling, sending a message, or otherwise activating the ringer/speaker electronics of the mobile terminal connected to the IED. The cell phone is the initiator and instead of a call causing the phone ringer to ring, the power for the ringer is typically sent to the detonator which detonates the explosive charge.
Since the cell phone is used in a criminal act, most terrorists use a prepaid Subscriber Identity Module (SIM) card in the initiator rather than a SIM card registered in the terrorists name. Obviously, a prepaid card, having no registration name is much harder to trace.
Currently jamming devices that are used to protect convoys traveling through known trouble areas also prevent any mobile terminals in a given area from accessing the network. One drawback to jamming is that legitimate users are denied access to the wireless system. In addition, these jamming devices essentially telegraph convoy movements by making all mobile terminals within the area of movement inoperable. Another problem is that tracking and locating devices work only when the mobile terminal is transmitting, so most of the time a “quiet” terminal (e.g., initiator cell phone in an IED) cannot be located.
What is needed is a method for suppressing the triggering of IEDs without revealing that convoy movement is imminent in a particular area and to do so in such as way that the potential to trace the call is enhanced. This solution must assume limited to no cooperation with mobile operators.